A cooling system for an engine transmission in a saddle type vehicle such as an all-terrain-vehicle. In one embodiment, the cooling system has an induction duct, connected to a belt case that houses a transmission, for inducting cooling air into the belt case. The system further includes a discharge duct connected to the belt case for exhausting the cooling air from the belt case, the discharge duct extending towards a rear fender of the vehicle. In addition, the system has an air exhaust aperture through which the cooling-air exits the discharge duct, the exhaust aperture located at an end of the discharge duct, the discharge duct generally forming an inverted "U" shape as viewed from a rear end of the vehicle, and the air exhaust aperture positioned so that the cooling air exiting the discharge duct does not directly strike the rear fender of the vehicle. The cooling system further has an induction box having a cooling-air induction port that allows the entrance of cooling-air into the induction box, the induction box being generally positioned in the transverse center of the vehicle, and the induction port being opened at a position near the bottom of a front fender of the vehicle.